The evolution of the current air transport system to the fully implemented Next Generation Air Transportation System (NGATS) will require substantial changes in the provision and use of aviation weather information. Several critical concepts have emerged in shaping the NGATS aviation weather system: network enabled weather information access, perfomance based services, and weather assimilation into decision loops.

In the case of the concept of network enabled weather information access, the principle goal is common situational awareness achieved through a real-time flow of information from private, commercial, and government sources with aircrat as additional nodes in the network. Obviously, new aircraft equipage will be required for pilots to access the (weather) information network need to be set, particularly for time critical weather information, and the roles and responsibilities of government, commercial, and private sources of weather information must be determined.

The idea behind the performance based services is that differnt services would be available to pilots depending upon their aircrafts' capabilities. Again, new aircraft equipage is likely necessary to take full advantage of NGATS capabilities. Pilots may need different types of weather information depending on the type of operation being conducted. This is a move away from the current "all available information" philosophy, necessitating the spawning of a set of new weather services.

The concept of weather assimilation into decision loops has at its core the principle of creating a single authoritative weather source. In addition, various decision support tools will account for the inherent uncertainty in weather when managing aircraft trajectories and weather hazards will be identified in real-time. Here again is the issue of roles and responsibilities for government, commercial, and private sources of weather information. In particular, will the database be the only "approved" source of weather data on which all weather products must be based? Who has the responsibility for disseminating hazardous weather information that comes from the database?

These new concepts and their implications present new challenges in the policy arena for the NGATS stakeholders. This paper presents an overview of policy challenges in provision of weather information and services as they pertain to public/private roles and responsibilities.